Quesh's rugged landscape is a result of the Quake, a massive geological event that occurred some fifty thousand years ago. Technically a series of groundquakes that lasted for three hundred years, the Quake caused Quesh's continents to move several meters apart, creating massive fissures in the ground. This in turn allowed the poisonous Quesh venom to rise up from the depths of Quesh and seep to the surface, leaving the atmosphere toxic to this day.
Quesh has been geologically stable for thousands of years now, but this has not stopped the Three Families from investing heavily in early warning systems; tremors one one-hundredth the size of the Quake could wipe out their refineries. Republic geologists have considered exploring the deepest caves exposed by the Quake, but until the caves are mined clear of Quesh venom, they are far too toxic to enter.